When aqueous macromolecular solutions are frozen, some water does not freeze. We have shown that this water, readily detectable by NMR, can be thought of as "bound" water which remains unfrozen because of its interactions with the macromolecule. This experiment is a sensitive probe of the role of water in maintaining the solution conformations of biopolymers because the amount of "bound" water and its NMR properties are quite different for different macromolecular shapes (e.g., native vs. denatured proteins or nucleic acids). We propose to identify the sites of water binding, the effects of conformation per se on water binding, and to study the hydration of cellular materials. Proposed experiments include studies of nucleic acids, pH and salt effects, and relaxation mechanisms. Some infrared experiments are also described.